* {
    margin: 0;
    padding: 0;
}

body {
    background-color: #999;
    font-size: 14px;
    margin: 0; /*顶部的灰色边框消失了*/
    padding: 0;

}

div.all {
    background-color: white;
    font-size: 14px;
    width: 75%;
    min-width: 800px; /*窗口宽度缩小时，最小为800*/
    margin: 0 auto; /*auto页面左右对齐*/
    border: 1px solid #333; /*包含内边距，包含外边距，包含边框*/
    border-style: none solid; /*去掉上下*/
    padding: 15px 30px;
}

div.introduce {
    margin: 16px 0 16px;
}

div.major {
    padding: 2.5em;
    margin: 0 590px 0 0;
    height: 7.5em;
    line-height: 1.8em;
    color: white;
    background-color: #03387a;
}

p {
    line-height: 1.5em;
    text-indent: 2em;
    margin: 0.5em 0 0.5em;
}

p.no_text_indent {
    text-indent: unset;
}

h1 {
    font-family: 黑体;
    color: #06c;
    font-weight: normal; /*删除粗细后，字体变粗，默认为粗体*/
    text-align: center;
    font-size: 3em;
    width: 100%;
    padding: 0.7em 1.2em;
    margin: 0;

}

h3 {
    font-family: 黑体;
    font-weight: normal;
    font-size: 150%;
    text-align: left;
    color: #06c;
    width: 100%;
    padding: 0.3em 0 0.2em;
}

a.back { /*返回目录*/
    color: blue;
    text-decoration-line: none;
}

a.back:hover {
    color: #f60;
    text-decoration-line: underline;
}

a.to {
    color: white;
    font-weight: bold;
    text-decoration-line: none;
}

a.to:hover {
    text-decoration-line: underline;
}

img {
    float: right;
    width: 590px;
    height: 12.5em; /*7.5+2*2.5(div高宽度=原始宽高度+内边距宽高度*/
}